Coagulation factor concentrates: past, present, and future

Factor Eight Inhibitor Bypassing Activity as First-line Therapy for Coagulopathy in Cardiac Surgery

OBJECTIVES

To compare the outcomes of factor eight inhibitor bypassing activity (FEIBA) versus fresh frozen plasma (FFP) as the primary treatment for postoperative coagulopathy in patients undergoing cardiac surgery.

DESIGN

A retrospective, propensity-matched study.

SETTING

A single, tertiary hospital.

PARTICIPANTS

Patients who underwent noncoronary cardiac surgery with cardiopulmonary bypass between 2015 and 2023.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We stratified patients into 2 groups based on whether they received intraoperative FFP or FEIBA; cases using both were excluded. We analyzed 434 cases, with 197 receiving FFP and 237 receiving FEIBA. After propensity matching, there was no significant difference in the proportion of the patients who required packed red blood cell transfusions (p = 0.08). However, of those who required packed red blood cell transfusions, patients in the FEIBA group required significantly fewer units of packed red blood cells (p < 0.001). Significantly fewer patients in the FEIBA group required platelet (p < 0.001) and cryoprecipitate (p < 0.001) transfusions. The FEIBA group showed decreased prolonged postoperative intubation (p = 0.05), decreased intensive care unit length of stay (p = 0.04), and lower 30-day readmission rates (p = 0.03). There were no differences in the rates of thrombotic complications between the 2 cohorts.

CONCLUSIONS

In the initial treatment of postcardiopulmonary bypass coagulopathy, FEIBA may be more effective than FFP in decreasing blood product transfusions and readmission rates. Further studies are needed to explore the potential routine use of FEIBA as first-line agent in this patient population.

Dosing, Monitoring, Blood Product Utilization, and Thromboembolic Complications of Four-Factor Prothrombin Complex Concentrate as Part of an Institutional Protocol in Pediatric Cardiac Surgery: A Retrospective Cohort Study

Pediatric cardiac surgery patients are predisposed to blood loss. Blood product administration can lead to complications. Prothrombin complex concentrates (PCCs) offer potential advantages of factor composition, small volume, decreased immunogenicity/infectious risks, and accessibility. The objective of this study was to describe dosing, monitoring, blood product utilization, and thromboembolic complications of administering four-factor PCC (4F-PCC) in pediatric cardiac surgery. We performed a retrospective review of patients aged <18 years undergoing cardiac surgery from June 2020 to May 2022 (inclusive) who received 4F-PCC. Outcomes of interest included 4F-PCC dosing (units/kg) and number of doses administered, chest tube output, blood product administration, donor exposure, length of stay, and thromboembolic events. Eighty-six patients met eligibility criteria. The median (range) age and weight were 0.37 (0.01-16.3) years and 5.3 (1.6-98) kg, respectively. Median (range) total 4F-PCC dose per patient was 25 (9.2-50) units/kg, with 6 patients (7%) receiving a total of two doses. Median (range) 24-hour postoperative packed red blood cells, platelet, plasma, and cryoprecipitate administration volumes were 0 (0-2.57) mL/kg/24 h, 0 (0-1.09), 0 (0-2.64), and 0 (0-0.28 mL/kg/24 h), respectively. Median (range) length of stay and 24-hour postoperative chest tube output were 10 (6-26) days and 1.1 (0.1-4.2) mL/kg/h, respectively. Two (2%) patients experienced a thromboembolic event within 30 days of 4F-PCC administration. These retrospective findings suggest no worsening of hemostatic parameters, a mild median improvement in fibrinogen, low blood product utilization, and low thromboembolism rates following 4F-PCC use in pediatric cardiac surgery.

Clinical analysis and quality of life survey of hemophilia B patients in the central and western regions of China

Objective

To study the current status of hemophilia B (HB) patients in the central and western regions of China.

Methods

This cross-sectional, multicenter study was conducted in seven provinces in the central and western regions of China from April 2019 to June 2023. Samples were collected for the factor IX activity, inhibitor screen, and gene mutation. Furthermore, the status of six index joints and quality of life (QoL) were assessed.

Results

A total of 185 HB patients (mild 15, moderate 75, and severe 95) with a median age of 12.17 years were enrolled. 30.3% (56/185) of patients had a family history of HB. 34.6% (64/185) of HB patients had diagnostic delay and 38.5% (69/179) experienced treatment delay. The incidence of inhibitors was 6.1% (11/179). We identified 123 genetic variants in this study, with missense mutations being the most common. 84.0% (89/106) of HB mothers were genetically identified as carriers, with 27.7% (13/47) of carriers having clotting factor levels less than 0.40 IU/ml. 71.4% (132/185) of HB patients had a history of joint hemorrhage, with a rate of target joint in these patients was 64.4% (85/132). Lower extremity joints were most often affected in patients. The Hemophilia Joint Health Score (HJHS) score was significantly positively correlated with the Hemophilia Early Arthropathy Detection with Ultrasound in China (HEAD-US-C) (r = 0.542, P < 0.001). Patients who received prevention treatment, inhibitor negative, without treatment delay, and without high-intensity replacement therapy showed a higher total score of the short form-36 health survey (SF-36).

Conclusions

One-third of HB patients had delay in diagnosis and treatment, and the incidence of inhibitors was 6.1%. Target joints were present in nearly half of HB patients. Missense was the main mutation type. 84.0% of mothers of HB patients in this study were found to be carriers. HEAD-US-C and HJHS can complement each other in the evaluation of joint status and give a valid basis for early clinical management. Early detection and preventive treatment, as well as reducing high-intensity replacement therapy and inhibitor generation, can effectively improve the QoL of patients.

Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic site

Background

Salvianolic acid B (SAB) is a major component of Salvia miltiorrhiza root (Danshen), widely used in East/Southeast Asia for centuries to treat cardiovascular diseases. Danshen depside salt, 85% of which is made up of SAB, is approved in China to treat chronic angina. Although clinical observations suggest that Danshen extracts inhibited arterial and venous thrombosis, the exact mechanism has not been adequately elucidated.

Objective

To delineate the antithrombotic mechanisms of SAB.

Methods

We applied platelet aggregation and coagulation assays, perfusion chambers, and intravital microscopy models. The inhibition kinetics and binding affinity of SAB to thrombin are measured by thrombin enzymatic assays, intrinsic fluorescence spectrophotometry, and isothermal titration calorimetry. We used molecular in silico docking models to predict the interactions of SAB with thrombin.

Results

SAB dose-dependently inhibited platelet activation and aggregation induced by thrombin. SAB also reduced platelet aggregation induced by adenosine diphosphate and collagen. SAB attenuated blood coagulation by modifying fibrin network structures and significantly decreased thrombus formation in mouse cremaster arterioles and perfusion chambers. The direct SAB-thrombin interaction was confirmed by enzymatic assays, intrinsic fluorescence spectrophotometry, and isothermal titration calorimetry. Interestingly, SAB shares key structural similarities with the trisubstituted benzimidazole class of thrombin inhibitors, such as dabigatran. Molecular docking models predicted the binding of SAB to the thrombin active site.

Conclusion

Our data established SAB as the first herb-derived direct thrombin catalytic site inhibitor, suppressing thrombosis through both thrombin-dependent and thrombin-independent pathways. Purified SAB may be a cost-effective agent for treating arterial and deep vein thrombosis.

Prothrombin Complex Concentrate versus Fresh Frozen Plasma in Adult Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-Analysis

Background

Prothrombin complex concentrate (PCC) and fresh frozen plasma (FFP) are commonly used to manage bleeding in patients during cardiac surgery. However, the relative efficacy and safety of these 2 strategies remain uncertain.

Methods

MEDLINE, Embase, and Cochrane were searched for studies comparing PCC and FFP in patients who underwent cardiac surgery complicated by bleeding. Review Manager (RevMan) ver. 5.4 (Nordic Cochrane Centre, The Cochrane Collaboration) was used for statistical analysis. Binary and continuous outcomes were compared using pooled risk ratios and mean differences, respectively. The meta-analysis protocol was registered in the International Prospective Register of Systematic Reviews under protocol number CRD42022379144.

Results

We included 8 studies with 1,500 patients, of whom 613 (40.9%) received PCC. The mean follow-up period ranged from 28 to 90 days. The PCC group had significantly lower chest tube drainage at 24 hours (mean difference [MD], -148.50 mL; 95% CI, -253.02 to -43.99 mL; p=0.005; I2=42%). Fewer units of red blood cells (RBCs) were transfused within the first 24 hours (MD, -1.02 units; 95% CI, -1.81 to -0.24 units; p=0.01; I2=56%), and fewer patients required RBC transfusion within the first 24 hours (risk ratio, 0.85; 95% CI, 0.78-0.93; p<0.007; I2=45%) in the PCC group. There were no statistically significant differences in secondary outcomes. Nonetheless, a subgroup analysis of randomized controlled trials failed to corroborate the results obtained from the main analysis.

Conclusion

Our findings suggest that PCC can be effective, without increased adverse events, when compared with FFP in patients undergoing cardiac surgery complicated by bleeding.

Use of Prothrombin Complex Concentrate in Oral Anticoagulant-Associated Major Bleeding

Severe bleeding remains the most significant adverse effect associated with both warfarin and the direct oral anticoagulant agents. Due to the life-threatening nature of these bleeds, knowledge and understanding of agents that are able to rapidly overcome the anticoagulation effects of these medications is paramount to their use. Worldwide, the most commonly used agent for this indication is prothrombin complex concentrate (PCC). This review summarizes the evidence on the use of PCC in this population and provides practical information regarding patient-specific administration considerations.

Upconversion nanoparticles regulated drug & gas dual-effective nanoplatform for the targeting cooperated therapy of thrombus and anticoagulation

Thromboembolism is the leading cause of cardiovascular mortality. Currently, for the lack of targeting, short half-life, low bioavailability and high bleeding risk of the classical thrombolytic drugs, pharmacological thrombolysis is usually a slow process based on micro-pumping. In addition, frequently monitoring and regulating coagulation functions are also required during (and after) the process of thrombolysis. To address these issues, a targeted thrombolytic and anticoagulation nanoplatform (UCATS-UK) is developed based on upconversion nanoparticles (UCNPs) that can convert 808 or 980 nm near-infrared (NIR) light into UV/blue light. This nanoplatform can target and enrich in the thrombus site. Synergistic thrombolysis and anticoagulation therapy thus could be realized through the controlled release of urokinase (UK) and nitric oxide (NO). Both in vitro and in vivo experiments have confirmed the excellent thrombolytic and anticoagulative capabilities of this multifunctional nanoplatform. Combined with the unique fluorescent imaging capability of UCNPs, this work is expected to contribute to the development of clinical thrombolysis therapy towards an integrated system of imaging, diagnosis and treatment.

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This work is not only the first application of UCNPs in the thrombolysis therapy, but also the first attempt to develop a dual effective drug & gas nanoplatform for thrombolytic & anticoagulation therapy.

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Besides conventional in vitro and animal experiments, a 3D printed vascular model is also constructed to further verify the feasibility of UCATS-UK.

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Through surface chemical modification, the nanoplatform possesses the capabilities of targeting thrombus, as well as light-controlled NO release for drug-free anticoagulation therapy.

Gut dysbiosis modulates the immune response to factor VIII in murine hemophilia A

The development of neutralizing FVIII antibodies is the most serious complication of hemophilia A treatment. The currently known patient- and treatment-related risk factors for inhibitor development do not accurately predict this adverse event in all patients. The composition of the gut microbiota has been shown to influence immune-mediated diseases at distant anatomical sites (eg, lungs, brain, and joints). We demonstrate that a disrupted gut microbiota can be created in a mouse model of hemophilia A using a broad-spectrum antibiotic. Under controlled conditions, this sustained dysbiosis was associated with an increase in splenic B cells and the development of higher titer, FVIII-specific immunoglobulin G antibodies after FVIII challenge. Splenic and mesenteric lymph node cytokines, T cells, and dendritic cells were unaffected before administration of FVIII. However, the immune transcriptome of both aforementioned secondary lymphoid organs was significantly modified. Short-chain fatty acids (SCFAs), which are immunomodulatory microbial metabolites, were depleted in cecal contents of the dysbiotic mice. Furthermore, supplementation of the drinking water with butyrate, the most immunologically active SCFA, successfully achieved attenuation of the FVIII immune response. Collectively, data from this exploratory study suggest that the composition of the gut microbiota alters the FVIII immune response via the action of specific microbial metabolites on the immune cell transcriptome and that oral supplementation with butyrate effectively reduces the FVIII immune response.

Factor XIII-A: An Indispensable "Factor" in Haemostasis and Wound Healing

Factor XIII (FXIII) is a transglutaminase enzyme that catalyses the formation of ε-(γ-glutamyl)lysyl isopeptide bonds into protein substrates. The plasma form, FXIIIA₂B₂, has an established function in haemostasis, with fibrin being its principal substrate. A deficiency in FXIII manifests as a severe bleeding diathesis emphasising its crucial role in this pathway. The FXIII-A gene (F13A1) is expressed in cells of bone marrow and mesenchymal lineage. The cellular form, a homodimer of the A subunits denoted FXIII-A, was perceived to remain intracellular, due to the lack of a classical signal peptide for its release. It is now apparent that FXIII-A can be externalised from cells, by an as yet unknown mechanism. Thus, three pools of FXIII-A exist within the circulation: plasma where it circulates in complex with the inhibitory FXIII-B subunits, and the cellular form encased within platelets and monocytes/macrophages. The abundance of this transglutaminase in different forms and locations in the vasculature reflect the complex and crucial roles of this enzyme in physiological processes. Herein, we examine the significance of these pools of FXIII-A in different settings and the evidence to date to support their function in haemostasis and wound healing.

Patients' Perception of the Impact of Innovation on Hemophilia Care Management Organization: A Qualitative Study Protocol (INNOVHEMO Study)

BACKGROUND

New therapies provide a favorable evolution in the care management of persons with hemophilia. However, the impact of these new therapies on patient care organization remains to be determined. A qualitative study will be implemented to analyze patients' perception regarding the impact of innovation on the organization of their care management. Secondary objectives will include refining specific factors related to persons with hemophilia (barriers or facilitators, especially the place of treatment) to consider within an organizational impact analysis.

PATIENTS AND METHODS

Semi-structured individual interviews will be conducted via videoconferencing or by phone by two researchers using an interview guide. Participants will be recruited from the Rhône-Alpes region, in France. Physicians from two hemophilia treatment centers will identify eligible patients. Moreover, a call for volunteers will be launched by the Rhône-Alpes committee of the French hemophilia association. Interviews will be conducted with adult patients, adolescent patients or parents of a minor with hemophilia regularly treated prophylactically or on demand. Data analysis will be performed with NVivo^® software. Each interview will be analyzed by two researchers using an inductive content analytic method.

DISCUSSION

The INNOVHEMO study is an original study analyzing the way patients perceive the impact of an innovation on their care management organization. The resulting patient-specific factors, identified as barriers or facilitators, will need to be integrated into a more comprehensive analysis of the impact of innovation on care management organization.

Pharmacological management of rare coagulation factor deficiencies besides hemophilia

INTRODUCTION

Rare coagulation factor deficiencies are less-known disorders with variable effects on the patient's life. Management of such patients is a challenge due to the paucity of evidence-based data, more so when patients with these rare disorders encounter a more rare, related condition, like inhibitor development or thrombosis.

AREA COVERED

A comprehensive literature search related to RCFDs and management was performed in PubMed in order to discuss therapeutic options and challenges, prophylaxis, management of minor and major surgeries, obstetric and gynecological complications, inhibitor development, and thrombosis.

EXPERT OPINION

Although significant changes have occurred in the management of RCFDs in recent years, more evidence-based studies besides expert opinion are needed for optimal management.

A European consensus statement on the use of four-factor prothrombin complex concentrate for cardiac and non-cardiac surgical patients

Modern four-factor prothrombin complex concentrate was designed originally for rapid targeted replacement of the coagulation factors II, VII, IX and X. Dosing strategies for the approved indication of vitamin K antagonist-related bleeding vary greatly. They include INR and bodyweight-related protocols as well as fixed dose regimens. Particularly in the massively bleeding trauma and cardiac surgery patient, four-factor prothrombin complex concentrate is used increasingly for haemostatic resuscitation. Members of the Transfusion and Haemostasis Subcommittee of the European Association of Cardiothoracic Anaesthesiology performed a systematic literature review on four-factor prothrombin complex concentrate. The available evidence has been summarised for dosing, efficacy, drug safety and monitoring strategies in different scenarios. Whereas there is evidence for the efficacy of four-factor prothrombin concentrate for a variety of bleeding scenarios, convincing safety data are clearly missing. In the massively bleeding patient with coagulopathy, our group recommends the administration of an initial bolus of 25 IU.kg^-1 . This applies for: the acute reversal of vitamin K antagonist therapy; haemostatic resuscitation, particularly in trauma; and the reversal of direct oral anticoagulants when no specific antidote is available. In patients with a high risk for thromboembolic complications, e.g. cardiac surgery, the administration of an initial half-dose bolus (12.5 IU.kg^-1 ) should be considered. A second bolus may be indicated if coagulopathy and microvascular bleeding persists and other reasons for bleeding are largely ruled out. Tissue-factor-activated, factor VII-dependent and heparin insensitive point-of-care tests may be used for peri-operative monitoring and guiding of prothrombin complex concentrate therapy.

Pharmacokinetics for haemophilia treaters: Meaning of PK parameters, interpretation pitfalls, and use in the clinic

Replacement therapy with concentrates of factor VIII or IX remains the gold standard for severe haemophilia management. The recent development of clotting factor products with extended half-life, widely available on the market since 2 years, facilitates adherence, improves considerably the patients' quality of life, and simplifies the management of breakthrough bleedings or surgery. These molecules have also brought to the limelight the concepts of optimization and personalization of anti-haemophilic prophylaxis. Pharmacokinetics (PK) is one of the tools that can help haematologists to adapt in a more objective and precise manner the prophylaxis regimen to each individual patient's specific needs. For many years, clinicians at haemophilia centres have been using some simple PK parameters, such as recovery and residual level. However, recently, they have been confronted with an important number of new PK parameters they were not familiar with, but that can be used to improve patient management. Due to the accumulation of PK data and their relative complexity, it is now necessary to analyse the relevance of the different PK parameters relative to haemophilia specificities, and also to know their limits to better use them.

The 3.2 Å structure of a bioengineered variant of blood coagulation factor VIII indicates two conformations of the C2 domain

BACKGROUND

Coagulation factor VIII represents one of the oldest protein-based therapeutics, serving as an effective hemophilia A treatment for half a century. Optimal treatment consists of repeated intravenous infusions of blood coagulation factor VIII (FVIII) per week for life. Despite overall treatment success, significant limitations remain, including treatment invasiveness, duration, immunogenicity, and cost. These issues have inspired research into the development of bioengineered FVIII products and gene therapies.

OBJECTIVES

To structurally characterize a bioengineered construct of FVIII, termed ET3i, which is a human/porcine chimeric B domain-deleted heterodimer with improved expression and slower A2 domain dissociation following proteolytic activation by thrombin.

METHODS

The structure of ET3i was characterized with X-ray crystallography and tandem mass spectrometry-based glycoproteomics.

RESULTS

Here, we report the 3.2 Å crystal structure of ET3i and characterize the distribution of N-linked glycans with LC-MS/MS glycoproteomics. This structure shows remarkable conservation with the human FVIII protein and provides a detailed view of the interface between the A2 domain and the remaining FVIII structure. With two FVIII molecules in the crystal, we observe two conformations of the C2 domain relative to the remaining FVIII structure. The improved model and stereochemistry of ET3i served as a scaffold to generate an improved, refined structure of human FVIII. With the original datasets at 3.7 Å and 4.0 Å resolution, this new structure resulted in improved refinement statistics.

CONCLUSIONS

These improved structures yield a more confident model for next-generation engineering efforts to develop FVIII therapeutics with longer half-lives, higher expression levels, and lower immunogenicity.

Safety and effectiveness of a prothrombin complex concentrate in approved and off-label indications

OBJECTIVE

To evaluate the effectiveness and safety of prothrombin complex concentrates (PCCs) in approved and off-label indications.

BACKGROUND

PCCs are approved for the urgent reversal of vitamin K antagonists (VKAs). Data concerning the efficacy, safety and dosing for off-label indications are limited, but they are included in massive bleeding protocols.

METHODS

This was a retrospective review of cases treated with four-factor PCCs (4F-PCCs) between January 2009 and 2016. Efficacy end-points include: (i) VKA reversal efficacy assessed by international normalised ratio (INR) normalisation (<1·5) and (ii) clinical efficacy as bleeding cessation and/or decreased number of transfused blood components and 24-h mortality in bleeding coagulopathy. The safety end-point is the incidence of thromboembolic events.

RESULTS

A total of 328 patients were included (51·8% male, median age 78 years old). Indications were as follows: VKA reversal (66·6%), bleeding coagulopathy (30·5%) and direct anticoagulant (DOAC) reversal due to bleeding (2·5%). VKA reversal was effective in 97·1% of patients, and 76·5% demonstrated complete reversal (INR < 1·5); only 34·3% patients needed hemoderivatives. Prior to emergency procedures, PCCs achieved global responses in 83% of patients, with no bleeding complication during intervention. DOAC reversal was effective in 88·9% of patients. Bleeding cessation was associated with the dose administered (P = 0·002). In coagulopathy bleeding, haemorrhage cessation, established by the International Society of Thrombosis and Haemostais (ISTH) definition, occurred in 56·7% of massive bleeding events and in 42·5% of other coagulopathies; 24-h mortality was 30%, mainly related to active bleeding. Ten thrombotic episodes were observed (3·1%).

CONCLUSION

4F-PCC was effective as adjuvant treatment with an acceptable safety profile, not only for the emergent reversal of VKAs but also for refractory coagulopathy associated with major bleeding.

Loss of fibrinogen in zebrafish results in an asymptomatic embryonic hemostatic defect and synthetic lethality with thrombocytopenia

Essentials Loss of fibrinogen in zebrafish has been previously shown to result in adult onset hemorrhage Hemostatic defects were discovered in early fga-/- embryos but well tolerated until adulthood Afibrinogenemia and thrombocytopenia results in synthetic lethality in zebrafish. Testing human FGA variants of uncertain significance in zebrafish identified causative mutations SUMMARY: Background Mutations in the alpha chain of fibrinogen (FGA), such as deficiencies in other fibrinogen subunits, lead to rare inherited autosomal recessive hemostatic disorders. These range from asymptomatic to catastrophic life-threatening bleeds and the molecular basis of inherited fibrinogen deficiencies is only partially understood. Zinc finger nucleases have been used to produce mutations in zebrafish fga, resulting in overt adult-onset hemorrhage and reduced survival. Objectives To determine the age of onset of hemostatic defects in afibrinogenemic zebrafish and model human fibrinogen deficiencies. Methods TALEN genome editing (transcription activator-like effector nucleases) was used to generate a zebrafish fga mutant. Hemostatic defects were assessed through survival, gross anatomical and histological observation and laser-induced endothelial injury. Human FGA variants with unknown pathologies were engineered into the orthologous positions in zebrafish fga. Results Loss of Fga decreased survival and resulted in synthetic lethality when combined with thrombocytopenia. Zebrafish fga mutants exhibit a severe hemostatic defect by 3 days of life, but without visible hemorrhage. Induced thrombus formation through venous endothelial injury was completely absent in mutant embryos and larvae. This hemostatic defect was restored by microinjection of wild-type fga cDNA plasmid or purified human fibrinogen. This system was used to determine whether unknown human variants were pathological by engineering them into fga. Conclusions These studies confirm that loss of fibrinogen in zebrafish results in the absence of hemostasis from the embryonic period through adulthood. When combined with thrombocytopenia, zebrafish exhibit synthetic lethality, demonstrating that thrombocytes are necessary for survival in response to hemorrhage.

Treatment of rare factor deficiencies other than hemophilia

The deficiency of fibrinogen, prothrombin, factor V (FV), FVII, FVIII, FIX, FX, FXI, and FXIII, called rare coagulation disorders (RCDs), may result in coagulopathies leading to spontaneous or posttrauma and postsurgery hemorrhages. RCDs are characterized by a wide variety of symptoms, from mild to severe, which can vary significantly from 1 disease to another and from 1 patient to another. The most typical symptoms of all RCDs are mucosal bleedings and bleeding at the time of invasive procedures, whereas other life-threatening symptoms such as central nervous system bleeding and hemarthroses are mostly present only in some deficiencies (afibrinogenemia, FX, and FXIII). At variance with hemophilia A and B and von Willebrand disease, RCDs are much less prevalent, ranging from 1 case in 500 000 to 1 in 2 million in the general population. Their clinical heterogeneity associated with the low number of patients has led to a delay in the development of appropriate therapies. Indeed, a similar heterogeneity can also be found in the treatment products available, ranging from the specific recombinant proteins to treat FVII- and FXIII-deficient patients to the complete absence of specific products to treat patients with FII or FV deficiencies, for whom prothrombin complex concentrates or fresh frozen plasma are, to date, the only option. The recent development of novel hemostatic approaches for hemophilia, such as the use of nonsubstitutive therapy as RNA interference, anti-tissue factor pathway inhibitor, and the gene therapy aimed at improving the patient's quality of life may also have an important role in the treatment of patients with RCDs in the future.

Utility of 4-Factor Prothrombin Complex Concentrate in Trauma and Acute-Care Surgical Patients

Context

Since 2013, prothrombin complex concentrate (PCCs) have been approved in the United States for the reversal of anticoagulation induced by vitamin K antagonists. However, there has been limited investigation into their use in trauma and acute-care surgery (ACS).

Objective

To investigate the role that 4-factor PCC may have in reversing anticoagulation in the setting of trauma and ACS.

Methods

All trauma and ACS patients who presented between March 14, 2014, and August 1, 2015, were included in this retrospective descriptive analysis. Patients receiving 4-factor PCC were compared with patients receiving fresh frozen plasma (FFP) alone. The following data were collected from medical records: age, sex, race, international normalized ratio (INR) at admission (baseline) and after reversal, blood products given, dosing of medication, injury severity score, length of stay, thromboembolic event, death during admission, and death within 90 days after admission.

Results

There were 188 trauma and ACS patients who required reversal of anticoagulation. Of these, 98 patients received FFP and 90 received PCC. Patients who received PCC were at increased risk for death during admission (20% vs 9.2% for FFP group) or within 90 days (39% vs 15%, respectively). Patients in the PCC group had a higher median baseline INR (2.9 vs 2.5 in the FFP group) and a lower postintervention INR (1.4 vs 1.8); consequently, the decrease in INR was greater in the PCC group than in the FFP group (1.5 vs 0.7, respectively). The number of total units of packed red blood cells transfused was significantly higher in patients receiving PCC.

Conclusion

Patients receiving PCC had worse outcomes than those who received FFP. Given that these differences may have resulted from baseline differences between groups, these results mandate further prospective analysis of the use of PCC in trauma and ACS patients.

Utility of prothrombin complex concentrate as first-line treatment modality of coagulopathy in patients undergoing liver transplantation: A propensity score-matched study

BACKGROUND

Transfusion management during liver transplantation (LT) is aimed at reducing blood loss and allogeneic transfusion requirements. Although prothrombin complex concentrate (PCC) has been used satisfactorily in various bleeding disorders, studies on its safety, and efficacy during LT are limited.

METHODS

A retrospective chart review of adult patients who underwent living donor LT at a single institute between October 2016 and January 2018 was carried out. The safety and efficacy of PCC in reducing transfusion requirements intraoperatively in patients who received PCC were compared with patients who did not receive PCC. A propensity score-matching technique was used, at a 1:1 ratio, to remove selection bias.

RESULTS

After completing the 1:1 propensity score-matched analysis, 60 pairs of patients were identified. The use of PCC was associated with significantly decreased red blood cell transfusion requirements (6.2 ± 4.1 vs 8.23 ± 5.18, P < 0.001) and fresh frozen plasma transfusion requirements (2.6 ± 2 vs 6.18 ± 4.1, P < 0.001). The number of patients developing postoperative hemorrhagic complications was higher in the non-PCC group.

CONCLUSIONS

During LT, the use of PCC led to decreased transfusion requirements. No thromboembolic complications related to PCC were noted in this series.

Optimizing transfusion strategies in damage control resuscitation: current insights

From clinical and laboratory studies of specific coagulation defects induced by injury, damage control resuscitation (DCR) emerged as the most effective management strategy for hemorrhagic shock. DCR of the trauma patient who has sustained massive blood loss consists of 1) hemorrhage control; 2) permissive hypotension; and 3) the prevention and correction of trauma-induced coagulopathies, referred to collectively here as acute coagulopathy of trauma (ACOT). Trauma patients with ACOT have higher transfusion requirements, may eventually require massive transfusion, and are at higher risk of exsanguinating. Distinct impairments in the hemostatic system associated with trauma include acquired quantitative and qualitative platelet defects, hypocoagulable and hypercoagulable states, and dysregulation of the fibrinolytic system giving rise to hyperfibrinolysis or a phenomenon referred to as fibrinolytic shutdown. Furthermore, ACOT is a component of a systemic host defense dysregulation syndrome that bears several phenotypic features comparable with other acute systemic physiological insults such as sepsis, myocardial infarction, and postcardiac arrest syndrome. Progress in the science of resuscitation has been continuing at an accelerated rate, and clinicians who manage catastrophic blood loss may be incompletely informed of important advances that pertain to DCR. Therefore, we review recent findings that further characterize the pathophysiology of ACOT and describe the application of this new information to optimization of resuscitation strategies for the patient in hemorrhagic shock.

Pharmacological reversal of the direct oral anticoagulants-A comprehensive review of the literature

The direct oral anticoagulants (DOACs) are used for stroke prevention in atrial fibrillation (SPAF) and the prevention and treatment of venous thromboembolic disease (VTE). Although DOAC-associated bleeding events are less frequent as compared to vitamin K antagonists, there is significant concern surrounding physicians' ability to evaluate and manage DOAC-associated bleeding when it does occur. Idarucizumab is a specific reversal agent for dabigatran and is the agent of choice for dabigatran reversal in the setting of major bleeding or urgent surgery/procedures. There are no commercially available specific reversal agents for the direct Xa inhibitors. Although they have not been rigorously studied in DOAC-treated patients requiring urgent anticoagulant reversal, limited evidence from in vitro studies, animal bleeding models, human volunteer studies (in vivo and in vitro) and case series suggest that coagulation factor replacement with prothrombin complex concentrate (PCC) and activated PCC (FEIBA) may contribute to hemostasis. However, the safety and efficacy of these agents and the optimal dosing strategies remain uncertain.

A reduction of prothrombin conversion by cardiac surgery with cardiopulmonary bypass shifts the haemostatic balance towards bleeding

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with blood loss and post-surgery thrombotic complications. The process of thrombin generation is disturbed during surgery with CPB because of haemodilution, coagulation factor consumption and heparin administration. We aimed to investigate the changes in thrombin generation during cardiac surgery and its underlying pro- and anticoagulant processes, and to explore the clinical consequences of these changes using in silico experimentation. Plasma was obtained from 29 patients undergoing surgery with CPB before heparinisation, after heparinisation, after haemodilution, and after protamine administration. Thrombin generation was measured and prothrombin conversion and thrombin inactivation were quantified. In silico experimentation was used to investigate the reaction of patients to the administration of procoagulant factors and/or anticoagulant factors. Surgery with CPB causes significant coagulation factor consumption and a reduction of thrombin generation. The total amount of prothrombin converted and the rate of prothrombin conversion decreased during surgery. As the surgery progressed, the relative contribution of α2-macroglobulin-dependent thrombin inhibition increased, at the expense of antithrombin-dependent inhibition. In silico restoration of post-surgical prothrombin conversion to pre-surgical levels increased thrombin generation excessively, whereas co-administration of antithrombin resulted in the normalisation of post-surgical thrombin generation. Thrombin generation is reduced during surgery with cardiopulmonary bypass because of a balance shift between prothrombin conversion and thrombin inactivation. According to in silico predictions of thrombin generation, this new balance increases the risk of thrombotic complications with prothrombin complex concentrate administration, but not if antithrombin is co-administered.

Partnering to change the world for people with haemophilia: 7th Haemophilia Global Summit, Madrid, Spain 22-24 September 2016

The 7th Haemophilia Global Summit was held in Madrid, Spain, in September 2016. With a programme designed, for the 6th consecutive year, by a Scientific Steering Committee of haemophilia experts, the aim of the summit was to share optimal management strategies for haemophilia at all life stages and to provide an opportunity for specialists from across the haemophilia multidisciplinary care team to engage in discussion and debate with leading international experts on current and future areas of research. Topics covered ranged from the optimisation of haemophilia management, emerging issues in clinical care, practical approaches and future perspectives, in addition to patient engagement and empowerment in modern haemophilia care.

Prothrombin Complex Concentrates in Pediatric Cardiac Surgery: The Current State and the Future

BACKGROUND

After decades of practice of pediatric cardiac surgery, postoperative bleeding due to the immaturity of hemostasis, hemodilution, and hypothermia remains a concern. Recently, a new approach for adult coagulopathy after bypass has emerged. Prothrombin complex concentrates (PCCs), designed to treat bleeding in hemophilia patients, are safely and efficiently used off label for hemorrhage after bypass. However, optimal dosing, indications and contraindications, and laboratory tests to assess the efficacy of PCC use in children have not yet been established. This literature review outlines the challenges of bypass-related coagulopathy, the pharmacology, and the experience in use of PCCs, with a focus on their potential in pediatric cardiac surgery.

METHODS

After a thorough literature search of MEDLINE, Scopus, and Ovid databases using the term "prothrombin complex concentrate AND pediatric," 23 relevant articles were selected.

RESULTS

The data supporting successful use of PCCs in acquired coagulopathy after cardiac surgery in adults have been increasing. Although small volume, low immunogenicity, efficiency, and speed in correcting coagulopathy are attractive qualities of PCCs for pediatric practice, current evidence is only anecdotal. The main concerns are unknown dosing regimens, the inability to closely monitor the effects of PCCs in real time, and a possibility of thrombotic complications, which can be particularly devastating in young congenital cardiac patients whose lives frequently depend upon the patency of artificial shunts.

CONCLUSIONS

Extensive, high-quality research is warranted to fill in the gaps of knowledge regarding using PCCs in pediatric cardiac practice.

Gene Therapy for Coagulation Disorders

Molecular genetic details of the human coagulation system were among the first successes of the genetic revolution in the 1980s. This information led to new molecular diagnostic strategies for inherited disorders of hemostasis and the development of recombinant clotting factors for the treatment of the common inherited bleeding disorders. A longer term goal of this knowledge has been the establishment of gene transfer to provide continuing access to missing or defective hemostatic proteins. Because of the relative infrequency of inherited coagulation factor disorders and the availability of safe and effective alternative means of management, the application of gene therapy for these conditions has been slow to realize clinical application. Nevertheless, the tools for effective and safe gene transfer are now much improved, and we have started to see examples of clinical gene therapy successes. Leading the way has been the use of adeno-associated virus-based strategies for factor IX gene transfer in hemophilia B. Several small phase 1/2 clinical studies using this approach have shown prolonged expression of therapeutically beneficial levels of factor IX. Nevertheless, before the application of gene therapy for coagulation disorders becomes widespread, several obstacles need to be overcome. Immunologic responses to the vector and transgenic protein need to be mitigated, and production strategies for clinical grade vectors require enhancements. There is little doubt that with the development of more efficient and facile strategies for genome editing and the application of other nucleic acid-based approaches to influence the coagulation system, the future of genetic therapies for hemostasis is bright.

Recombinant Factor VIIa–Mediated Activation of Prothrombin Complex Concentrates

Recombinant factor VIIa (rFVIIa) is used in the management of bleeding in patients with hemophilia. A generic biosimilar version of NovoSeven is also developed (AryoSeven). To compare the activation profile of NovoSeven and AryoSeven, 2 commercially available protein complex concentrates (PCCs) were used. Profilnine activated by RecombiPlasTin 2G resulted in conversions of prothrombin to prethrombin and thrombin at 5 to 30 minutes. However, addition of rFVIIa at final concentration range of 0.25 to 0.5 µg/mL to the same mixture resulted in total conversion of prothrombin to thrombin with a doublet at 36 kDa. Recombinant factor VIIa alone did not generate thrombin in native Beriplex, and the addition of rFVIIa to Beriplex failed to generate thrombin. Beriplex activated by RecombiPlasTin 2G resulted in complete conversion of prothrombin to thrombin. Both NovoSeven and AryoSeven exhibited similar activation profiles. These studies indicate that the activation of PCCs by both rFVIIa preparations results in comparable generation of thrombin.

Once-weekly prophylactic dosing of recombinant factor IX improves adherence in hemophilia B

Regular prophylactic treatment in severe hemophilia should be considered an optimal treatment. There is no general agreement on the optimal prophylaxis regimen, and adherence to prophylaxis is a main challenge due to medical, psychosocial, and cost controversies. Improved approaches in prophylaxis regimen of hemophilia B are needed to make patients’ lives easier. There is some evidence to support the efficacy of once-weekly prophylaxis. Longer sampling schedules are required for the determination of pharmacokinetic (PK) properties of factor IX (FIX). The half-life of FIX seems to be longer than previously described and is expected to be 34 hours. The clinical significance of maintaining a 1% trough level is widely debated in hemophilia B. The overall relationship between factor concentrate levels and incidence of joint bleeding was found to be very weak. Data also indicate that the distribution of FIX into an extravascular FIX compartment may contribute to hemostasis independently of circulating plasma FIX levels. Clinical assessment of the frequency and severity of bleeds remain an important measure of the efficacy of treatment. Role of PK-guided therapy remains to be established. Two prospective randomized studies had evaluated the efficacy and safety of 100 IU/kg once-weekly prophylaxis with nonacog alfa, and this prophylaxis regimen was found to be associated with lower annual bleeding rate compared with on-demand treatment in adolescents and adults with moderately severe-to-severe hemophilia B. Secondary prophylaxis therapy with 100 IU/kg nonacog alfa once weekly reduced annual bleeding rate by 89.4% relative to on-demand treatment. Residual FIX may be supportive of effectiveness. Once-weekly prophylaxis was well tolerated in the two studies, with a safety profile similar to that reported during the on-demand treatment period. To individually tailor treatment to clinical response and to minimize costs of factor concentrate, it would be of interest to investigate the efficacy of lower doses of the drug administered once a week.

Prothrombin Complex Concentrates for Bleeding in the Perioperative Setting

Prothrombin complex concentrates (PCCs) contain vitamin K-dependent clotting factors (II, VII, IX, and X) and are marketed as 3 or 4 factor-PCC formulations depending on the concentrations of factor VII. PCCs rapidly restore deficient coagulation factor concentrations to achieve hemostasis, but like with all procoagulants, the effect is balanced against thromboembolic risk. The latter is dependent on both the dose of PCCs and the individual patient prothrombotic predisposition. PCCs are approved by the US Food and Drug Administration for the reversal of vitamin K antagonists in the setting of coagulopathy or bleeding and, therefore, can be administered when urgent surgery is required in patients taking warfarin. However, there is growing experience with the off-label use of PCCs to treat patients with surgical coagulopathic bleeding. Despite their increasing use, there are limited prospective data related to the safety, efficacy, and dosing of PCCs for this indication. PCC administration in the perioperative setting may be tailored to the individual patient based on the laboratory and clinical variables, including point-of-care coagulation testing, to balance hemostatic benefits while minimizing the prothrombotic risk. Importantly, in patients with perioperative bleeding, other considerations should include treating additional sources of coagulopathy such as hypofibrinogenemia, thrombocytopenia, and platelet disorders or surgical sources of bleeding. Thromboembolic risk from excessive PCC dosing may be present well into the postoperative period after hemostasis is achieved owing to the relatively long half-life of prothrombin (factor II, 60-72 hours). The integration of PCCs into comprehensive perioperative coagulation treatment algorithms for refractory bleeding is increasingly reported, but further studies are needed to better evaluate the safe and effective administration of these factor concentrates.

Optimizing Thrombin Generation with 4-Factor Prothrombin Complex Concentrates in Neonatal Plasma After Cardiopulmonary Bypass

BACKGROUND

Bleeding is a serious complication after pediatric cardiopulmonary bypass (CPB) that is associated with an increase in perioperative morbidity and mortality. Four-factor prothrombin complex concentrates (4F-PCCs) have been used off-label to supplement transfusion protocols for bleeding after CPB in adults; however, data on their use in neonates are limited. In this study, we hypothesized that 4F-PCCs administered ex vivo to neonatal plasma after CPB will increase thrombin generation.

METHODS

Fifteen neonates undergoing complex cardiac repairs requiring CPB were enrolled in this prospective study. Arterial blood was obtained after anesthesia induction but before CPB (baseline), after CPB following heparin reversal, and after our standardized transfusion of a quarter of a platelet apheresis unit (approximately 20 mL·kg) and 3 units of cryoprecipitate. Kcentra (CSL Behring), a 4F-PCC with nonactivated factor VII (FVII), and factor 8 inhibitor bypassing activity (FEIBA; Baxter Healthcare Corporation), a 4F-PCC with activated FVII, were added ex vivo to plasma obtained after CPB to yield concentrations of 0.1 and 0.3 IU·mL. Calibrated automated thrombography was used to determine thrombin generation for each sample.

RESULTS

The addition of Kcentra to plasma obtained after CPB resulted in a dose-dependent increase in the median (99% confidence interval) peak amount of thrombin generation (42.0 [28.7-50.7] nM for Kcentra 0.1 IU·mL and 113.9 [99.0-142.1] nM for Kcentra 0.3 IU·mL). The rate of thrombin generation was also increased (15.4 [6.5-24.6] nM·min for Kcentra 0.1 IU·mL and 48.6 [29.9-66.6] nM·min for Kcentra 0.3 IU·mL). The same was true for FEIBA (increase in peak: 39.8 [27.5-49.2] nM for FEIBA 0.1 IU·mL and 104.6 [92.7-124.4] nM for FEIBA 0.3 IU·mL; increase in rate: 17.4 [7.4-28.8] nM·min FEIBA 0.1 IU·mL and 50.5 [26.7- 63.1] nM·min FEIBA 0.3 IU·mL). In the posttransfusion samples, there was a significant increase with Kcentra in the median (99% confidence interval) peak amount (41.1 [21.0-59.7] nM for Kcentra 0.1 IU·mL and 126.8 [106.6- 137.9] nM for Kcentra 0.3 IU·mL) and rate (18.1 [-6.2 to 29.2] nM·min for Kcentra 0.1 IU·mL and 53.2 [28.2-83.1] nM·min for Kcentra 0.3 IU·mL) of thrombin generation. Again, the results were similar for FEIBA (increase in peak: 43.0 [36.4-56.7] nM for FEIBA 0.1 IU·mL and 109.2 [90.3-136.1] nM for FEIBA 0.3 IU·mL; increase in rate: 25.0 [9.1-32.6] nM·min for FEIBA 0.1 IU·mL and 59.7 [38.5-68.7] nM·min for FEIBA 0.3 IU·mL). However, FEIBA produced in a greater median reduction in lag time of thrombin generation versus Kcentra in samples obtained after CPB (P = 0.003 and P = 0.0002 for FEIBA versus Kcentra at 0.1 and 0.3 IU·mL, respectively) and in samples obtained after transfusion (P < 0.0001 for FEIBA versus Kcentra at 0.1 and 0.3 IU·mL).

CONCLUSIONS

After CPB, thrombin generation in neonatal plasma was augmented by the addition of 4F-PCCs. The peak amount and rate of thrombin generation were enhanced in all conditions, whereas the lag time was shortened more with FEIBA. Our findings suggest that the use of 4F-PCCs containing activated FVII may be an effective adjunct to the initial transfusion of platelets and cryoprecipitate to augment coagulation and control bleeding in neonates after CPB.

Blood coagulation factor XIII and factor XIII deficiency

Factor XIII (FXIII) is a multifunctional pro-γ-transglutaminase that, in addition to its well-known role in hemostasis, has a crucial role in angiogenesis, maintenance of pregnancy, wound healing, bone metabolism, and even cardio protection. FXIII deficiency (FXIIID) is a rare bleeding disorder (RBD) with an estimated incidence of one per two million that is accompanied by life-threatening bleeding such as umbilical cord bleeding, recurrent spontaneous miscarriage, and intracranial hemorrhage (ICH). Today, the disease is successfully managed by FXIII concentrate and recombinant FXIII for prophylaxis, management of minor and major bleeding, treatment of ICH, and successful delivery in women with recurrent pregnancy loss. Molecular analysis of patients with FXIIID revealed a wide spectrum of mutations, most frequently missense mutations in the FXIII-A subunit, with a few recurrent mutations observed worldwide. In vitro expression studies revealed that most of the missense mutations cause intracellular instability of the FXIII protein and, subsequently, FXIIID.

Safety surveillance in haemophilia and allied disorders

The introduction of clotting factor concentrates has transformed the lives of persons with inherited bleeding disorders. With the use of prophylactic treatment, it is now possible to prevent bleeding in these individuals. The early concentrates were contaminated with the HIV and hepatitis C viruses (HCV) and resulted in major morbidity and mortality in the recipients. Current products are much safer, especially in terms of infectious agents, but other adverse events such as alloantibodies (inhibitors), allergic reactions and thrombotic risks remain of concern. Approximately 30% of previously untreated patients with severe haemophilia A develop inhibitors, making this the most important issue in haemophilia care today. Recently, it was suggested that one of the most commonly used concentrates was associated with a higher inhibitor risk, but this was not supported by the evidence from all studies. Good safety surveillance systems are essential for all diseases and products but are particularly so in the group of individuals with inherited bleeding disorders treated with clotting factor concentrates who have suffered disproportionately from the adverse effects of their treatment. National and multinational systems are now in place to allow reporting of adverse events in patients with inherited bleeding disorders. All clinicians treating individuals with inherited bleeding disorders should prospectively report adverse events to treatment even if they are believed to be common and well recognized.

New developments in the management of moderate-to-severe hemophilia B

Hemophilia B is an X-linked genetic deficiency of coagulation factor IX (FIX) activity associated with recurrent deep tissue and joint bleeding that may lead to long-term disability. FIX replacement therapy using plasma-derived protein or recombinant protein has significantly reduced bleeding and disability from hemophilia B, particularly when used in a prophylactic fashion. Although modern factor replacement has excellent efficacy and safety, barriers to the broader use of prophylaxis remain, including the need for intravenous (IV) access, frequent dosing, variability in individual pharmacokinetics, and cost. To overcome the requirement for frequent factor dosing, novel forms of recombinant FIX have been developed that possess extended terminal half-lives. Two of these products (FIXFc and rIX-FP) represent fusion proteins with the immunoglobulin G1 (IgG1) Fc domain and albumin, respectively, resulting in proteins that are recycled in vivo by the neonatal Fc receptor. The third product has undergone site-specific PEGylation on the activation peptide of FIX, similarly resulting in a long-lived FIX form. Clinical trials in previously treated hemophilia B patients have demonstrated excellent efficacy and confirmed less-frequent dosing requirements for the extended half-life forms. However, gaps in knowledge remain with regard to the risk of inhibitor formation and allergic reactions in previously untreated patient populations, safety in elderly patients with hemophilia, effects on in vivo FIX distribution, and cost-effectiveness. Additional strategies designed to rebalance hemostasis in hemophilia patients include monoclonal-antibody-mediated inhibition of tissue factor pathway inhibitor activity and siRNA-mediated reduction in antithrombin expression by the liver. Both of these approaches are long acting and potentially involve subcutaneous administration of the drug. In this review, we will discuss the biology of FIX, the evolution of FIX replacement therapy, the emerging FIX products possessing extended half-lives, and novel “rebalancing” approaches to hemophilia therapy.

Pharmacokinetics and pharmacodynamics of SCT800, a new recombinant FVIII, in hemophilia A mice

AIM

SCT800 is a new third-generation recombinant FVIII agent that is undergoing promising preclinical study. This study aimed to investigate the pharmacokinetic and pharmacodynamic profiles of SCT800 in hemophilia A mice.

METHODS

After hemophilia A mice were intravenously injected with single dose of SCT800 (80, 180, and 280 IU/kg) or the commercially available product Xyntha (280 IU/kg), pharmacokinetics profiles were evaluated based on measuring plasma

FVIII

C. For pharmacodynamics study, dose-response curves of SCT800 and Xyntha (1-200 IU/kg) were constructed using a tail bleeding model monitoring both bleeding time and blood loss.

RESULTS

Pharmacokinetics profile analysis showed a dose independency of SCT800 ranging from 80 to 280 IU/kg and comparable pharmacokinetic profiles between SCT800 and Xyntha at the doses tested. Pharmacodynamics study revealed comparable ED50 values of SCT800 and Xyntha in the tail bleeding model: 14.78 and 15.81 IU/kg for bleeding time, respectively; 13.50 and 13.58 IU/kg for blood loss, respectively. Moreover, at the doses tested, the accompanying dose-related safety evaluation in the tail bleeding model showed lower hypercoagulable tendency and wider dosage range potential for SCT800 than Xyntha.

CONCLUSION

In hemophilia A mice, SCT800 shows comparable pharmacokinetics and pharmacodynamics to Xyntha at the doses tested, and possibly with better safety properties.

Safety and efficacy of prothrombin complex concentrate as first-line treatment in bleeding after cardiac surgery

BACKGROUND

Bleeding after cardiac surgery requiring surgical reexploration and blood component transfusion is associated with increased morbidity and mortality. Although prothrombin complex concentrate (PCC) has been used satisfactorily in bleeding disorders, studies on its efficacy and safety after cardiopulmonary bypass are limited.

METHODS

Between January 2005 and December 2013, 3454 consecutive cardiac surgery patients were included in an observational study aimed at investigating the efficacy and safety of PCC as first-line coagulopathy treatment as a replacement for fresh frozen plasma (FFP). Starting in January 2012, PCC was introduced as solely first-line treatment for bleeding following cardiac surgery.

RESULTS

After one-to-one propensity score-matched analysis, 225 pairs of patients receiving PCC (median dose 1500 IU) and FFP (median dose 2 U) were included. The use of PCC was associated with significantly decreased 24-h post-operative blood loss (836 ± 1226 vs. 935 ± 583 ml, p < 0.0001). Propensity score-adjusted multivariate analysis showed that PCC was associated with significantly lower risk of red blood cell (RBC) transfusions (odds ratio [OR] 0.50; 95% confidence interval [CI] 0.31-0.80), decreased amount of RBC units (β unstandardised coefficient -1.42, 95% CI -2.06 to -0.77) and decreased risk of transfusion of more than 2 RBC units (OR 0.53, 95% CI 0.38-0.73). Patients receiving PCC had an increased risk of post-operative acute kidney injury (AKI) (OR 1.44, 95% CI 1.02-2.05) and renal replacement therapy (OR 3.35, 95% CI 1.13-9.90). Hospital mortality was unaffected by PCC (OR 1.51, 95% CI 0.84-2.72).

CONCLUSIONS

In the cardiac surgery setting, the use of PCC compared with FFP was associated with decreased post-operative blood loss and RBC transfusion requirements. However, PCC administration may be associated with a higher risk of post-operative AKI.

Increased inhibitor incidence in severe haemophilia A since 1990 attributable to more low titre inhibitors

Many studies have reported an increased incidence of inhibitors in previously untreated patients (PUPs) with severe haemophilia A after the introduction of recombinant products. It was the objective of this study to investigate whether the inhibitor incidence has increased between 1990 and 2009 in an unselected cohort of PUPs with severe haemophilia A (FVIII< 1 %). Patients were consecutively recruited from 31 haemophilia treatment centres in 16 countries and followed until 50 exposure days or until inhibitor development. Inhibitor development was studied in five-year birth cohorts comparing cumulative incidences. Furthermore the risk for inhibitor development per five-year birth cohort was studied using multivariable Cox regression, adjusting for potential genetic and treatment-related confounders. A total of 926 PUPs were included with a total cumulative inhibitor incidence of 27.5 %. The inhibitor incidence increased from 19.5 % in 1990-1994 (lowest) to 30.9 % in 2000-2004 (highest; p-value 0.011). Low titre inhibitor incidence increased from 3.1 % in 1990-1994 to 10.5 % in 2005-2009 (p-value 0.009). High titre inhibitor incidences remained stable over time. After 2000, risk of all inhibitor development was increased with adjusted hazard ratios 1.96 (95 % CI 1.06-2.83) in 2000-2004 and 2.34 (1.42-4.92) in 2005-2009. Screening for inhibitors was intensified over this 20-year study period from a median of 1.9 to 2.9 tests/year before 2000 to 2.7 to 4.3 tests/year after 2000. In conclusion, the cumulative inhibitor incidence has significantly increased between 1990 and 2009. The high titre inhibitor incidence has remained stable.

Clotting factor product administration and same-day occurrence of thrombotic events, as recorded in a large healthcare database during 2008-2013

BACKGROUND

Thrombotic events (TEs) are serious adverse events that can occur following administration of clotting factors (CFs).

OBJECTIVES

To evaluate occurrence of same-day TEs for different CF products and potential risk factors.

METHODS

A retrospective cohort study of individuals exposed to CF products during 2008-2013 was conducted using a large commercial insurance database. CF products were identified by procedure codes, and TEs were ascertained via diagnosis codes. Crude same-day TE rates (per 1000 persons exposed) were estimated overall and by congenital factor deficiency (CFD) status, CF products, age and gender. Multivariable logistic regression analyses were used to control for confounding. Laboratory analysis was used to compare the procoagulant activities of FIX products.

RESULTS

Of 3801 individuals exposed to CFs, 117 (30.8 per 1000) had same-day TEs recorded. The crude same-day TE rate was higher for CF users without CFD, 70.2 (102 of 1452), as compared with those with CFD, 6.4 (15 of 2349) (RR, 11.0; 95% CI, 6.4-18.9). For individuals without CFD, a significantly increased same-day TE risk was identified for factor IX complex (OR, 6.92; 95% CI, 3.11-15.40), factor VIIa (OR, 9.42; 95% CI, 4.99-17.78) and other products when compared with fibrin sealant. An increased risk of a TE was found with older age (≥ 45 years), history of TEs and underlying health conditions. The laboratory identified elevated procoagulant activity in Profilnine(®) and Benefix(®) .

CONCLUSIONS

The study shows an increased same-day TE risk for CF users without CFD and suggests substantial off-label CF use. The study findings also show elevated same-day TE rates for different CF products and suggest the importance of product properties and patient factors.

Managing target-specific oral anticoagulant associated bleeding including an update on pharmacological reversal agents

Target-specific oral anticoagulants (TSOACs) dabigatran, rivaroxaban and apixaban are approved for the prevention and treatment of thromboembolism in several clinical settings. Bleeding is the major complication of anticoagulant therapy, including TSOACs, and anticoagulant reversal strategies are highly desired for the management of anticoagulant-associated major bleeding in addition to maximum supportive care and procedural/surgical intervention. Unlike VKAs for which vitamin K and coagulation factor replacement with prothrombin complex concentrate (PCC) can restore hemostasis, there are no clinically available agents proven to reverse TSOAC anticoagulant effect and ameliorate TSOAC-related major bleeding. This narrative review critically evaluates the evidence for TSOAC reversal using non-specific reversal agents PCC, activated PCC (APCC) and recombinant activated factor VII (rVIIa) which have been assessed primarily using in vitro experiments, animal models and healthy human volunteers. Aripazine is a novel agent undergoing clinical development for non-specific anticoagulant reversal, including TSOACs. Data are presented regarding specific reversal agents idarucizumab (dabigatran) and andexanet alfa (oral factor Xa inhibitors) currently being evaluated in clinical trials. A practical approach to management of patients with TSOAC-associated bleeding is also provided. There is an urgent need for clinical studies that evaluate the efficacy and safety of reversal strategies for TSOAC-related major bleeding with assessment of clinical outcomes such as bleeding and mortality.